CT Angiogram

What is a CT angiogram?

A computed tomography (CT) angiogram is a test that makes detailed pictures of your blood vessels and nearby tissues. The most common reason to have a CT angiogram is to see if you have narrowed or blocked coronary arteries (coronary artery disease). When done for these reasons, the test is sometimes called a coronary CT angiogram, or CCTA.

But a CT angiogram is useful for many other purposes, too. For example, it can help diagnose:

• Aneurysm. There’s an abnormal bulge or widening of a blood vessel, like your aorta or an artery in your brain.
• Aortic dissection. There’s a tear in the inner layer of your aorta’s wall.
• Arteriovenous malformation. Arteries and veins are tangled up in a specific area, like your brain.
• Carotid artery disease. Arteries that send blood to your brain have plaque buildup.
• Peripheral artery disease. Arteries in your legs or arms have plaque buildup.
• Pulmonary embolism. A blood clot has traveled to your lungs.
• Spontaneous coronary artery dissection (SCAD). There’s a separation or tear in the wall of a coronary artery.
• Traumatic injury. Blunt or penetrating trauma to any part of your body (like your chest, neck or head) has damaged blood vessels there.

Your provider may also use a CT angiogram to plan a procedure or surgery. For example, they might look at your coronary arteries before a procedure such as a heart valve replacement, heart bypass surgery or stent placement.

Technically, a CT angiogram is the picture the test produces. And CT angiography is the name of the imaging technique. But people often use both terms to refer to the test you go in to get. You might also see this test called CTA.

How does CT angiography work?

All CT scans produce detailed, 3D images of the inside of your body. This is because a scanner takes hundreds of 2D (flat) pictures. Then, a computer puts all these pictures together to form high-quality 3D images. But contrast dye is what makes the difference between a CT scan and CT angiography. 

The combination of CT scanning and contrast dye produces “lit up” images of your blood vessels. Your healthcare provider can rotate each 3D image. It’s a bit like holding a model of your blood vessel in their hand. They can see each part of the vessel from different angles. This lets them get a close-up view to pinpoint any problems and plan treatment.

CT angiography is less invasive and has fewer risks than traditional angiography. For a traditional angiogram, a catheter moves inside your blood vessels until it reaches the part providers want to see. You don’t need this catheter for a CT angiogram. Based upon your age and other medical conditions, you may not be an ideal candidate for a CT angiogram and may still require a more invasive traditional angiography procedure.

How to prepare

The healthcare provider who requested your CT angiogram will tell you how to prepare. In general, you should tell your provider:

• All medicines you’re currently taking
• Your full medical history, including heart conditions, kidney problems and allergies
• If you’ve ever had an allergic reaction to contrast dye used in a test
• If you’re pregnant or breastfeeding

Your healthcare provider will give you specific instructions to follow. These will tell you:

• How many hours to fast (not eat anything) before the test
• If you should stop taking any of your usual medicines before the test

When you arrive, you’ll put on a hospital gown. You’ll also need to remove any jewelry or metal objects that you’re wearing. These could interfere with the test.

What to expect during a CT angiogram

CT angiography is typically quick and painless. However, it does require an IV catheter to be inserted into your arm. You’re awake and don’t need anesthesia. You’ll lie on an exam table that moves through a large ring that looks a bit like a doughnut. You’re not as enclosed as you would be for an MRI.

During the test, you’ll need to stay very still so the scanner can take good pictures. A specially trained healthcare provider called a radiologic technologist will perform your test. They’ll explain each step and tell you exactly what you need to do (like when to hold your breath). Here are the general steps:

1. You’ll lie down flat on the exam table.
2. Your provider will help you get comfortable. They may use pillows and straps to help you stay in place.
3. Your provider will insert an IV into a vein so they can give you the contrast dye. They’ll likely use a vein in your hand or arm. The IV will stay in place until all the picture-taking is done. You might feel a brief sense of warmth come over you as the dye goes in. This is harmless.
4. If the test is looking at your coronary arteries, your provider will stick little patches (EKG leads) on your chest. This lets your provider take pictures in sync with your heartbeat.
5. When everything’s ready, your provider will move to a separate room. They can still see you and talk with you through an intercom system.
6. The exam table will slowly move through the opening of the scanner (the doughnut-like ring). During this time, the scanner takes hundreds of pictures. You might hear some buzzing sounds or clicking.
7. Your provider will tell you when to hold your breath or lie extra still. Tiny movements can affect image quality.
8. Once your provider has enough pictures, they’ll remove the IV and put a bandage on your skin there. They’ll help you get up from the exam table. At this point, the test is done.

You can expect to be in the testing room for about 20 to 60 minutes, including prep time. You’ll spend about one to two minutes in the scanner. This should go by fast. But you might need to go through the scanner more than once so your provider can get all the pictures they need.

What are the disadvantages of a CT angiogram?

Depending on your needs and concerns, CT angiography may have some disadvantages. These include:

• The use of contrast dye. For most people, this isn’t a problem. But it’s possible to have an allergic reaction to the dye. If you’ve had such a reaction in the past, your provider may give you medicine to take before the test. Or they may recommend a different test.
• Low-dose radiation exposure. The radiation you get from one test is very small. Over a lifetime, radiation exposure may add up to slightly raise your risk for cancer. Your provider takes all of this into account. Usually, the benefits of a CTA outweigh any risks.

What can I expect after my CT angiogram?

When your test is done, you can return to your usual routine. You should drink lots of water and other liquids. This helps flush the contrast dye out of your system.

What type of results do you get from CTA?

CT angiography produces detailed images of your blood vessels and nearby tissues (including capillary beds). These images can show a wide range of issues, like plaque buildup, aneurysms and more. A radiologist will review and interpret these images. They’ll share the findings with the healthcare provider who requested your test. Your provider will schedule a time to go over the results with you. 

You may need follow-up visits with your provider. You may also need further testing. Your provider will explain next steps. Don’t hesitate to ask questions about the results and what they mean for you.

When should I call my doctor?

Call your provider if:

• You have questions as you’re preparing for your CT angiogram
• You have questions about the results
• You want to discuss your diagnosis or treatment options